1. Field of the Invention
The present invention relates to a new and useful shielded envelope for mailing floppy disk cartridges, used in information processing systems.
2. Description of the Prior Art
Floppy disk cartridges are well known in the art and used extensively in computers and other information processing systems for storage of information signals. The disk itself on which information signals are stored is a circular device which has a magnetic coating on at least one side thereof. The disk is enclosed in an essentially rectangular plastic jacket which includes an outer cover and a non-abrasive liner. Accordingly, a floppy disk cartridge is an assembly of the jacket and the disk.
It is very important that the floppy disk cartridge be treated with care to prevent inadvertent damage to the disk or non-reproducibility of the information stored thereon. Floppy disks are susceptible to extreme temperature conditions, exposure to electric and magnetic fields, static electric discharge, as well as dust and dirt. Exposure to such conditions may adversely affect the operation of the floppy disk cartridge and the reproducibility of the stored information. For these reasons, the industry has found it advantageous to store floppy disk cartridges in protective envelopes, during transportation or mailing.
The protective envelopes currently on the market comprise basically a rear wall and a front wall joined together at the bottom and two opposite sides to form an open pocket, which is dimensioned to receive the floppy disk cartridge. The height of the rear wall may be greater than that of the front wall so that it extends beyond the opening of the pocket. Such a design allows the cartridge to be easily inserted into and removed from the protective envelope. The depth of the pocket formed by joining the rear and front wall of the protective envelope is usually about two-thirds to three-fourths greater than the diameter of the floppy disk. Prior art examples of structurally protective envelopes include U.S. Pat. No. 4,473,153 granted to Colangelo on Sep. 25, 1984, U.S. Pat. No. 4,623,325 granted to Mori et al on Nov. 18, 1986, and U.S. Pat. No. 4,852,740 granted to Sellar et al on Mar. 11, 1988.
U.S. Pat. No. 4,473,153, is a representative example of prior art floppy disk cartridge protective envelopes. The flexible disk cartridge envelope of U.S. Pat. No. 4,473,153 basically comprises a single sheet of paper material or the like which is shaped or folded to form a front wall, a rear wall, and a protective cover or flap. The front and rear walls are joined on three sides at corresponding peripheral edges by either side flaps or folds to form an open pocket dimensioned to receive at least a portion of the disk cartridge. The height of the rear wall may be greater than that of the front wall so that a portion of the rear wall extends above the opening of the pocket. The protective cover is pivotally joined to the outermost edge of the rear wall extension and should have a length at least equal to the distance the rear wall projects above the pocket opening. In this manner, the cover can be pivoted away from the pocket opening so that a disk cartridge contained in the pocket can be removed, or pivoted downward to meet the front wall so that the disk cartridge is entirely enclosed within the protective envelope.
The envelope may further include a locking device to insure that the envelope remains closed. This locking device may comprise recontact adhesive applied to the covers so that the cover adheres to the front wall of the envelope when in the closed position.
Furthermore, the paperlike material used to construct the paper envelope in accordance with the prior art patents should be of a thickness to provide the protective envelope with sufficient rigidity The material may be uncoated, coated, or coated one sided paper, or a spun bonded olefin commonly referred to by the trade name Tyvek. Alternatively, the envelope may be entirely or partially formed of a vinyl material. A portion of the surfaces of the envelope which are exposed when the cover is in the closed position may be covered with a protective coating. Actual choice of construction material may be based on strength, rigidity, smoothness, anti-static, anti-lint, or any other desired properties.
Due to their size, closing features, and weight the protective envelopes taught by the aforementioned prior art patents are not suitable for mailing. While U.S. Pat. No. 4,653,639 granted to Traynor on Mar. 31, 1987 does describe a protective envelope reportedly suitable for mailing, Traynor does not teach or suggest any protection of the floppy disks from ambient electromagnetic energy. Likewise, none of the other prior art protective envelopes cited above teach or suggest the electromagnetic shielding of the floppy disk.
The coating or covering of material used to construct protective envelopes is also known in the prior art as, for example, in U.S. Pat. No. 4,355,718 granted to Hagelberg on Oct. 26, 1982. Hagelberg teaches a grammaphone record jacket having an electrically conducting material applied to the inner side (broad) surfaces of the jacket for the purpose of discharging electrostatic charge that may build up on the grammaphone record surfaces. However, there is no disclosure or suggestion in Hagelberg of covering all the inner edge surfaces, or the desirability of doing so.
There are many inherent problems associated with the application of electrically conductive coatings to the prior art protective envelopes. In particular, such coatings lack resiliency in flexure and, therefore, have a tendency to crack causing electrical discontinuities within the surfaces of the protective envelopes. This cracking may manifest itself during the opening and closing of aforementioned protective covers or during its manufacture. Similarly, said coatings, when applied, tend to be discontinuous or inconsistent in thickness and electrical continuity. These inherent features in the prior art result in inefficient shielding protection from electromagnetic impulses or static electric discharge.
As floppy disks have become more prominent as a means for storing information, integrity of data, especially during mailing, has become of increasing concern to the user. Ambient electromagnetic energy can easily erase or alter magnetically stored data. Floppy disks can come into contact with electromagnetic energy at any time during their trip through the postal system. Post Office sorting equipment, power cables, power equipment, and the like are just a few examples of electromagnetic energy sources.